Drinking mug



FIG. 1 is a side elevational view of a drinking mug showing my new design, the side opposite is a mirror image thereof;

FIG. 2 is a top plan view thereof;

FIG. 3 is a bottom plan view thereof;

FIG. 4 is a rear elevational view thereof; and

FIG. 5 is a front elevational view thereof. 

The ornamental design for a drinking mug, as shown and described. 